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Wind turbines in the context of integration in an urban environment are considered as one of the most promising technologies for the efficient diffusion of renewable energy sources. However, situations such as low wind velocity, highly turbulent and skewed wind flow conditions are commonly encountered in this environment. This misaligned flow could affect the horizontal axis wind turbine performance. The vertical axis wind turbine (VAWT) is more suitable to operate under these unfavorable conditions. Nevertheless, the conventional VAWT has low efficiency and poor self-starting characteristics. Therefore, a novel design of deflector integrated cross axis wind turbine (CAWT) is proposed. Tests were carried out to harness wind energy from both the horizontal and vertical components of the skewed flow induced by the deflectors. A semi-empirical approach was also developed to analyse the performance of the CAWT. The aerodynamic behaviour of the CAWT was determined by combining the blade element momentum (BEM) model and double multiple streamtube theory (DMST). The approach showed notable agreement between the experimental and theoretical results (9.8%–14.2% difference). In conclusion, the findings from the experiment and the model showed that the concept has very good potential in the renewable energy industry.

Three-dimensional numerical simulations have been performed to analyze the aerodynamic characteristics of a straight-bladed NACA0021 vertical axis wind turbine (VAWT). The unsteady flow CFD simulation was validated with the wind tunnel experiment data available in the literature. Sliding mesh method with the SST k-ω turbulence model was employed to simulate the rotational motion of the VAWT using ANSYS Fluent. The study showed a good agreement between the simulation and the wind tunnel testing. Further simulations were carried out to study the effects of a flat plate deflector being placed at the upwind of the VAWT by varying a few parameters including the position, the inclination angle and the length of the flat plate deflector. The simulations showed that the augmented flow occurred at the near wake region where the flow was accelerated and deflected by the deflector before impinging with the turbine; hence the coefficient of power (CP) of the VAWT improved significantly. However, the performance of the VAWT was highly dependent on the position of the deflector. From the simulation results, with the optimum parameters, the cycle-averaged coefficient of torque was increased about 47.10% higher compared to the VAWT without the deflector.

Power augmentation features have been proven as one of the wind turbine performance enhancement methods particularly for vertical axis wind turbines (VAWTs). Researches showed that with the aid of a deflector, shroud or a single plate, the power output of a VAWT can be increased remarkably. In this paper, lab tests and simulations were performed to investigate the aerodynamic effects and the flow field around a flat plate deflector as a power augmentation device which is placed at the lower upstream of a micro H-rotor VAWT. From the study, the deflector is able to induce a high velocity wind at the near-wake region which was about 25% higher compared to the oncoming wind velocity. The deflected wind flows improve the performance significantly as well as reduce the self-start velocity of the turbine. Nonetheless, it is highly dependent on the positioning of the flat plate deflector. Both experiment and simulation showed a notable observation on the position effect of the flat plate deflector. From the lab test, with the deflector at the optimal position, the maximum coefficient of power (CP) achieved was 7.4% increment compared to the bare turbine. Also, from the simulation, the optimal position showed an improvement of averaged CP up to 33% compared to the bare turbine. The flat plate deflector is simple, low cost, and can be easily retrofitted to existing stand-alone VAWT systems to improve the efficiency making them suitable for on-site power generation in urban and isolated places.

In unfavourable wind conditions, factors such as low wind speed, high turbulence, and constant wind direction change can reduce the power production of a horizontal axis wind turbine. Certain vertical axis wind turbine design principles perform well under these harsh operating conditions; but, these wind rotors typically have low power coefficients. To overcome the problems above, a novel cross axis wind turbine has been conceptualised to maximise wind energy generation. This is achieved via harnessing the wind energy from both the horizontal and vertical components of the oncoming wind. The cross axis wind turbine comprises three vertical blades and six horizontal blades arranged in a cross axis orientation. Initial testing using deflectors to guide the oncoming airflow upward showed that the cross axis wind turbine produced significant improvements in power output and rotational speed performance compared to a conventional straight-bladed vertical axis wind turbine. In particular, it was found that the cross axis wind turbine integrated with a 45° deflector produced a power coefficient 2.8 times higher than the vertical axis wind turbine. The rotor rotational speed was increased by 70% with well-improved starting behaviour. Initial computational fluid dynamics analysis was done to illustrate the flow field of the deflected air stream by an omni-directional shroud. The simulation showed that the approaching air is deflected upwards by the guide-vane, which would interact with the horizontal blades and produce additional torque. The cross axis wind turbine is applicable in many locations, creating significant opportunities for wind energy devices and therefore reducing dependencies on fossil fuel.

This Article presents a Brief of the various types of Pollutants that are contributing to the problem of air pollution in Malaysia, As well as the mention of some episodes in air pollution that have given rise to concern here

The novel exhaust air energy recovery turbine generator is designed to recover part of energy from a fan-powered exhaust air system which represented by a cooling tower. The discharge wind from the cooling tower varies throughout the radius makes it a non-uniform profile. A vertical axis wind turbine (VAWT) is placed at the outlet of a cooling tower to recover the energy. The VAWT behavior in the non-uniform wind stream from the exhaust air system is studied by experiment and double multiple stream tube (DMST) theory. A novel application of the DMST model is applied for non-uniform wind stream. The experimental results show that best horizontal position of the VAWT is at a distance of about 2/3 of the outlet radius with respect to turbine rotation. Theoretical analysis explains the wind turbine behavior in the non-uniform wind stream as acquired from the experiment. For the selected wind turbine, it is the best to match the highest wind velocity region to the wind turbine at the range of 45° to 115° azimuth angle. This innovative system has a huge potential due to wide application of exhaust air system globally.

There are many advantages of vertical axis wind turbines (VAWTs) compared with horizontal axis wind turbines (HAWTs). Research has shown that VAWTs are more suitable for turbulent wind flow and urban applications. However, the efficiency and low self-start ability of VAWTs are always the main drawbacks especially for the lift-type VAWTs. Unlike HAWTs, the rotor blades for VAWTs do not always provide positive torque during operation. Many innovative designs have been implemented to improve the performance of VAWTs, and this includes different configurations and blade profiles. This paper extensively reviews various flow augmentation systems and attempts to provide information to researchers on current augmentation techniques and other relevant research. The flow augmentation system is able to increase the coefficient of power, CP, hence improving the output power of different types of VAWTs. Some augmentation systems are able to increase the maximum power output by up to 910%. The methods and designs used to increase upwind velocity and to reduce negative torque created on the wind turbine have been discussed in detail. Additionally, the flow augmentation devices that are integrated with building structures are also reported in this paper.

A novel cross axis wind turbine (CAWT) which comprises of a cross axis blades arrangement was presented and investigated experimentally. The CAWT is a new type of wind turbine that extracts wind energy from airflows coming from the horizontal and vertical directions. The wind turbine consists of three vertical blades and six horizontal blades arranged in a cross axis orientation. Hubs in the middle of the CAWT link the horizontal and vertical blades through connectors to form the CAWT. The study used a 45° deflector to guide the oncoming airflow upward (vertical wind direction). The results from the study showed that the CAWT produced significant improvement in power output and rotational speed performance compared to a conventional straight-bladed vertical axis wind turbine (VAWT), where the CAWT C Pmax is 2.5 times higher than the C Pmax produced by the VAWT for the same wind speed of 4.5 m/s.

Situations such as low wind speed, high turbulence and frequent wind-direction change can reduce the performance of horizontal axis wind turbine (HAWT). Certain vertical axis wind turbine (VAWT) designs have the ability to operate well in these harsh operating conditions but they possess low power coefficient generally. In order to tackle the mentioned problems, a novel cross-axis-wind-turbine (CAWT) is conceptualized to extract wind energy from both the horizontal and vertical directions of the on-coming winds to maximize the wind energy generation. The CAWT consists of three vertical blades and six horizontal blades arranged in cross axis orientation. Initial testing showed that maximum RPM generated by the CAWT is 166% higher than the VAWT under the same experimental conditions with well-improved starting behavior. Computational Fluid Dynamics (CFD) analysis was done to illustrate the flow field of the deflected and channeled air stream by omni-directional shroud. The air stream deflected upwards by the guide vane interacts with the horizontal blades. The CAWT is applicable in a wide variety of locations, creating significant opportunities for the use of wind energy devices and therefore alleviating dependencies on fossil fuel.

The aim of this study is to present the performance of an innovative wind–solar-rain water hybrid renewable energy generator and harvester roof system. A novel V-shape roof guide vane (VRGV) that located above the vertical axis wind turbine (VAWT) is introduced to guide and increase the wind speed by the venturi effect before it interacts with the rotor blades, hence improve the performance of the wind turbine. 2D CFD simulations was carried out to verify the optimized effect of VRGV out of nine different angles of roof designs and to estimate the increased speed by the VRGV. From the simulations, the optimum inclination arrangement of the V-shape roof guide vane is 25°. The wind speed augmented factor of the VRGV was 44%, from 2.00 m/s to 2.88 m/s. The working concept of the VRGV is to minimize the negative torque zone of a VAWT and to reduce turbulence and rotational speed fluctuation. Besides, the design of the VRGV that blends into the building architecture can be aesthetic as well. An experimental setup has been developed to verify the effect of VRGV using a prototype. Anemometric measurements were used to calculate the power of wind turbine. The system was also designed to provide optimum surface area and orientation for solar power generation. An automatic cooling and cleaning system with a stream of rain water was designed to clean and cool the roof which can improve the electrical efficiency of the solar photovoltaic modules. The ventilation vents of the system allow warm air inside the building to be ventilated out from the building by the pressure difference. The skylighting in the system improve the living comfort level and reduce power consumption of artificial lighting.

A technical feasibility study of an innovative hybrid solar-wind-rain eco-roof system with natural ventilation and skylight for electrical energy generation and saving is presented in this paper. The system integrates and optimizes five green technologies: wind turbine, solar photovoltaic system, rain water harvesting and utilization system, natural ventilation and roof sky lighting. The design was conceptualized based on the experiences acquired from meteorological data for Malaysian application. The V-shape top roof which was designed above the wind turbine was able to increase the wind speed by the venturi effect before the wind interacts with the wind turbine located between the roofs, hence improve the performance of the wind turbine. An automatic cooling and cleaning system with a stream of water was designed to clean and cool the roof which can improve the electrical efficiency of the solar photovoltaic modules. The ventilation vents of the system allow warm air inside the building to be ventilated out from the building by the pressure difference caused by high speed wind due to the roof design. The skylighting in the system improve the living comfort level and reduce power consumption of artificial lighting. Technical assessment of the system showed the estimated annual energy generated was 21205.65 kWh, estimated energy savings was 1839.6 kWh, the estimated annual ventilation rate was 2.17 × 108 m3 and reduction of CO2 emissions was 17767.89 kg/yr.

Thermal comfort in the building is a major concern among the design expertise especially in tropical countries. Therefore, it is important to design a smart roof system to reduce the heat gain of the building and enhance the resident's thermal comfort. The leading feature of this system is using PVC tubes integrated with a layer of insulation material and fans and located at the underside of the roof to act as a moving-air path (MAP) system. Indoor experiment is carried out on the scale roof model and the heat transfer rate into the attic is determined using experimental data. Next, Adaptive Neuro Fuzzy Inference System (ANFIS) is applied as a soft-computing method determine the predominant variables that affecting the thermal comfort in the building. Training and testing data of the ANFIS model are collected from the experimental measurement. Mass flow rate, solar-air temperature, inlet air temperature, outlet air temperature and ambient temperature are the input parameters used to compute the output parameter which is the attic temperature. The results indicated that the combination of mass flow rate and ambient temperature is the primary factor and the best predictor accuracy for thermal comfort in the building.

The microwave assisted pyrolysis of oil palm fiber (OPF) for production of hydrogen rich gas was experimentally investigated by considering different reaction parameters. Five different OPF sample sizes (i.e., lengths less than 1 mm, 1–3 mm, 4–6 mm, 7–9 mm and 10–12 mm), microwave power ranging from 400 W to 900 W, reaction temperatures ranging from 450 °C to 700 °C and N 2 flow rates ranging 200–1200 cm 3 min −1 were tested. The hydrogen and the total gas yield from all process parameters have been reported. The microwave assisted pyrolysis was carried out by using a microwave reactor which has a capacity of providing 2450 ± 25 MHz microwave frequency. It has been found that the use of a smaller OPF particle sizes, a higher microwave power, a higher reaction temperature and a higher N 2 flow rates significantly yields more H 2 rich gas. The char produced at the maximum hydrogen yield process parameter was considered for TGA and SEM analyses and the results shows a potential use for the soil fertilization.

This paper introduces the Eco-Greenergy™ hybrid wind-solar photovoltaic energy generation system and its applications. The system is an integration of the novel omni-direction-guide-vane (ODGV) with a vertical axis wind turbine (VAWT). The ODGV is designed to surround the VAWT for wind power augmentation by creating a venturi effect to increase the on-coming wind speed before it interacts with the turbine blades. In wind tunnel tests, the ODGV improves the power output of the VAWT by 3.48 times compared with a bare VAWT at its peak torque. Furthermore, the rotor rotational speed of the wind turbine increased by 182% at 6 m/s of wind speed. A solar PV panel can be mounted on the top surface of the ODGV for solar energy generation. Estimation on wind-solar energy output shows that the system can generate a total of 572.8 kWh of energy per year. By comparison, the ODGV increases the annual wind energy output by 438%. The green energy generated from the hybrid system can be used to power LED lights or other appliances (e.g., CCTV camera).

The prospect of harnessing wind energy in urban areas is not promising owing to low wind speeds and the turbulence caused by surrounding obstacles. However, these challenges can be overcome through an improved design of wind turbine that can operate efficiently in an urban environment. This paper presents a novel design of a building integrated cross axis wind turbine (CAWT) that can operate under dual wind direction, i.e., horizontal wind and vertical wind from the bottom of the turbine. The CAWT consists of six horizontal blades and three vertical blades for enhancing its self-starting behavior and overall performance. The study employed a mock-up building model with gable rooftop where both of the developed CAWT and the conventional straight-bladed vertical axis wind turbine (VAWT) are mounted and tested on the rooftop. The height of the CAWT and the VAWT above the rooftop was varied from 100 to 250 mm under the same experimental conditions. The results obtained from the experimental study showed that there is significant improvement in the coefficient of power (Cp) and self-starting behavior of the building integrated CAWT compared to the straight-bladed VAWT. At 100 mm height, the Cp,max value of the CAWT increased by 266%, i.e., from 0.0345 to 0.1263, at tip speed ratio (TSR) (λ) of 1.1 and at wind speed of 4.5 m/s. Similar improvements in performance are also observed for all condition of CAWT heights above the rooftop where the CAWT outperformed the straight-bladed VAWT by 196%, 136% and 71% at TSR of 1.16, 1.08, and 1.12 for Y = 150, 200, and 250 mm, respectively. Moreover, the CAWT performs better at 10° pitch angle of the horizontal blade compared to other pitch angles.

An assembly of two vertical axis wind turbines (VAWTs) and an enclosure is installed above a cooling tower to harness the discharged wind for electricity generation. The enclosure consists of guide-vanes and diffuser-plates, is used to enhance the rotational speed of the turbines for power augmentation. The angle of the guide-vanes is optimized to ensure the oncoming wind stream impinges the rotor blades of the turbine at an optimum angle. The diffuser-plates are tilted at an optimum angle to increase the discharged airflow rate. The performance of the system is tested in the laboratory followed by a field test on an actual size cooling tower. The VAWT performance is increased in the range of 7–8% with the integration of enclosure. There is no significant difference in the current consumption of the fan motor between the bare cooling tower and the one with installed VAWTs. With the presence of this system, approximately 17.5 GW h/year is expected to be recovered from 3000 units of cooling towers at commercial areas, assuming the cooling tower is driven by a 7.5 kW fan motor and operates 16 h/day. This amount of recovered energy can also be translated into 13% reduction in CO2 emission.

The exhaust air energy recovery wind turbine generator is an on-site clean energy generator that utilizes the advantages of discharged air which is strong, consistent and predictable. Two vertical axis wind turbines (VAWTs) in cross-wind orientation which are integrated with an enclosure are installed above a cooling tower to harness the discharged wind for electricity generation. It is mounted at a specific distance and position above the cooling tower outlet. The enclosure (consisting of several guide-vanes and diffuser-plates) acts as a wind power-augmentation device to improve the performance of the VAWTs. The guide-vanes are placed in between the discharged air outlet and the wind turbine. They are designed to guide the on-coming wind stream to an optimum flow angle before it interacts with the rotor blades. The diffuser-plates are built extended from the outlet duct of the exhaust air system. They are tilted at an optimum angle to draw more wind and accelerate the discharged air flow. A particular concern related to public safety which may be due to blade failure is minimized since the VAWTs are contained inside the enclosure. The performance of the VAWTs and its effects on the cooling tower's air intake speed and current consumption of the power-driven fan were investigated. A laboratory test was conducted to evaluate the effectiveness of the energy recovery wind turbine (5-bladed H-rotor with 0.3 m diameter) generator on a cooling tower model. The results showed a reduction in the power consumption of the fan motor for cooling tower with energy recovery turbine compared to the normal cooling tower while the intake air speed increased. Meanwhile, the VAWT's performance was improved by a 7% increase in rotational speed and 41% reduction in response time (time needed for the turbine to reach maximum rotational speed) with the integration of the enclosure. This system can be used as a supplementary power for building lighting or fed into electricity grid for energy demand in urban building. The energy output is predictable and consistent, allowing simpler design of the downstream system. The fact that there is an abundance of cooling tower applications and unnatural exhaust air resources globally causes this to have great market potential.

The indoor thermal comfort is the basic thing for each and every occupant, not only in tropical areas but also all over the world. It is necessary to make an energy efficient roof design and to improve the indoor condition of the building. This paper is focused on the roof design to develop the ventilation system so as to obtain low attic temperature without effecting the environment and keep the interior of the building cool. In the present study, four identical roof models were fabricated to carry out laboratory tests to evaluate their performances. In the roof models, aluminum (Al) tubes were used as a moving-air path (MAP) which acts as a ventilation channel. These channels allows the natural ventilation to take out hot air to the outside. In addition, an insulation layer and ventilation fans were integrated with the Al tubes to get better performance. For the combination of those features, the results revealed that the attic temperature was reduced remarkably, compared to the ordinary roof model. This comprehensive roof model will be the most suitable to the environment and applicable for its improved performance.

This paper presents an idea on generating green energy by extracting discharged wind energy from a cooling tower. Two vertical axis wind turbines (VAWTs) integrated with a wind power-augmentation device are installed above a cooling tower to harness unnatural wind for electricity generation. The wind power-augmentation device is built with several guide-vanes and diffuser-plates to improve the performance of the VAWTs. Guide-vanes are designed to create a venturi effect and guide the on-coming wind stream to an optimum flow angle which is matched to the optimum angle of attack of the VAWTs. Diffuser-plates are tilted at an optimum angle to draw more wind and accelerate the discharged airflow. From the laboratory test, the VAWTs performance was increased by 7 – 8 % when guide-vanes and diffuser-plates are installed at their optimum angle. The correct matching of VAWTs for this system is expected to generate electricity at their rated power constantly when the cooling tower is in operation. This system can contribute to the reduction of greenhouse gases emission and conservation of the environment for a healthier life since fossil fuel consumption for energy generation is reduced as well as efficient use of energy.

Recently, there are small wind turbine developments which are suitable for urban and suburban application. However, the efficiency of the wind turbine is the main concern for all researchers due to the uncertainty of wind speed and wind direction in urban area. In this paper, a new power augmented shroud integrated with vertical axis wind turbine (VAWT) is introduced. This power augmented shroud is able to improve the performance of the VAWT significantly by increasing the wind speed. It also channels the flow to better angle of attack for the VAWT and reduces the negative torque of the wind turbine. Hence, it improves the self-starting behaviour of the VAWT, and increases the coefficient of power. The numerical method is used to simulate the wind flow for the power augmented shroud with a single bladed NACA 0015 airfoil VAWT by commercial computational fluid dynamic (CFD) software, ANSYS FLUENT 14.0. In this 2D simulation, the shear stress transport (SST) k-ω turbulence model with the sliding mesh method was used with the tip speed ratio of 5.1 for the wind turbine. The result was verified by re-simulating the experiment published by the Sandia National Laboratories. The simulation result shows that the new design of power augmented shroud is able to increase the coefficient of power significant for the VAWT which is about 147.1% compared to the bare VAWT. Therefore, for urban area application, this power augmented shroud can improve the low efficiency problem for the VAWT.

An innovative idea on extracting clean energy from man-made wind resources with micro wind turbine system for power generation is introduced in this paper. This system generates on-site clean energy using a micro wind generation system. A vertical axis wind turbine (VAWT) with an enclosure is mounted above a cooling tower’s exhaust fan to harness the wind energy for producing electricity. The VAWT is positioned at a specific position at the cooling tower outlet to avoid a negative impact on the performance of the cooling tower. The enclosure can act as a safety cover and also enhance the performance of the VAWT. It is designed with several guide-vanes positioned at the up-stream side of the wind turbine to create a venturi effect and guide the wind before it interacts with the turbine blades. Moreover, the enclosure design is comprised of diffuser-plates that can draw more wind and accelerate the flow. Laboratory test conducted on a scaled model shows no measurable difference in the air intake speed and current consumption of the power-driven fan when the turbine was spinning above the cooling tower. Field test on an actual induced-draft cooling tower shows no significant difference on the outlet air speed of the cooling tower. A small difference was observed on the power consumption by the fan motor which is 0.39% higher with the presence of the VAWT. This system is retrofit-able to existing cooling towers and has very high market potential due to abundant cooling towers and other unnatural exhaust air resources globally.

Cool roof systems play a significant role in enhancing the comfort level of occupants by reducing the attic temperature of the building. Heat transmission through the roof can be reduced by applying thermal insulation coating (TIC) on the roof and/or installing insulation under the roof of the attic. This paper focuses on a TIC integrated with a series of aluminium tubes that are installed on the underside of the metal roof. In this study, the recycled aluminium cans were arranged into tubes that act as a moving-air-cavity (MAC). The TIC was formulated using titanium dioxide pigment with chicken eggshell (CES) waste as bio-filler bound together by a polyurethane resin binder. The thermal conductivity of the thermal insulation paint was measured using KD2 Pro Thermal Properties Analyzer. Four types of cool roof systems were designed and the performances were evaluated. The experimental works were carried out indoors by using halogen light bulbs followed by comparison of the roof and attic temperatures. The temperature of the surrounding air during testing was approximately 27.5 C. The cool roof that incorporated both TIC and MAC with opened attic inlet showed a significant improvement with a reduction of up to 13 C (from 42.4 C to 29.6 C) in the attic temperature compared to the conventional roof system. The significant difference in the results is due to the low thermal conductivity of the thermal insulation paint (0.107 W/mK) as well as the usage of aluminium tubes in the roof cavity that was able to transfer heat efficiently.

This paper investigates a technology-driven solution to supply a portion of energy demand in future green cities. An idea on harnessing unnatural wind resources for electricity is presented. Two vertical axis wind turbines with an enclosure are mounted above a cooling tower to recover part of the energy from the exhaust air. Guide-vanes are designed to create a venturi effect and guide the wind before it interacts with the turbine blades. Diffuser-plates help to draw more wind and accelerate the exhaust airflow. Safety concerns that may result from blade failure are minimized by the design of the enclosure. From the laboratory test and field test results, there is no significant difference in the current consumption of the fan motor with the installation of the wind turbines. The integration of the enclosure has shown an improvement on the turbine’s rotational speed which is 30.4% higher. The electricity generated from this system can be fed into the electricity grid. For 3000 units of cooling tower (2 m outlet diameter powered by a 7.5 kW fan motor and operated for 16 hours/day), 13% of the energy to power the fan motor is expected to be recovered from this system which equals 17.5 GWh/year.

A shrouded wind turbine system has a number of potential advantages over the conventional wind turbine. A novel power-augmentation-guide-vane (PAGV) that surrounds a Sistan wind turbine was designed to improve the wind rotor performance by increasing the on-coming wind speed and guiding it to an optimum flow angle before it interacts with the rotor blades. The integration of the PAGV into the 3-in-1 wind, solar and rain water harvester on high-rise buildings has been illustrated. A particular concern related to public safety is minimized when the wind turbine is contained inside the PAGV and noise pollution can be reduced due to the enclosure. Besides, the design of the PAGV that blends into the building architecture can be aesthetic as well. Moreover, a mesh can be mounted around the PAGV to prevent the bird-strike problem. From the wind tunnel testing measurements where the wind turbine is under free-running condition (only rotor inertia and bearing friction were applied), the wind rotor rotational speed (with the PAGV) was increased by 75.16%. Meanwhile, a computational fluid dynamics (CFD) simulation shows that the rotor torque was increased by 2.88 times with the introduction of the PAGV. Through a semi-empirical method, the power output increment of the rotor with the PAGV was 5.8 times at the wind speed of 3 m/s. Also, the flow vector visualization (CFD) shows that a larger area of upstream flow was induced through the rotor with the PAGV.

An innovative 3-in-1 wind–solar hybrid renewable energy and rain water harvester is designed for urban high rise application. A novel power-augmentation-guide-vane (PAGV) that surrounds the Sistan rotor vertical axis wind turbine (VAWT) is introduced to guide and increase the speed of the high altitude free-stream wind for optimum wind energy extraction. The system was also designed to provide optimum surface area and orientation for solar power generation. On the top surface of the PAGV, rain water can be collected, thereby reducing the electrical power required to pump water to the upper levels of the high rise building. To minimize the visual impact, the outer design of the PAGV can be blended into the building architecture. The system is also designed to eliminate the bird-strike problem and the concern on safety, and reduce the vibration. Wind tunnel testing on the scaled down prototype shows that the PAGV improved the starting behavior and increased the rotational speed of the Sistan rotor VAWT by 73.2% at the wind speed of 3 m/s. According to the present study, with the 30 m diameter and 12 m high PAGV integrated system, the estimated annual energy generated and savings is 160 MW h.

A novel shrouded wind-solar hybrid renewable energy and rain water harvester with an omni-directional-guide-vane (ODGV) for urban high-rise application is introduced. The ODGV surrounds the vertical axis wind turbine (VAWT) and enhances the VAWT performance by increasing the on-coming wind speed and guiding it to an optimum flow angle before it interacts with the rotor blades. An ODGV scaled model was built and tested in the laboratory. The experimental results show that the rotational speed of the VAWT increases by about 2 times. Simulations show that the installation of the ODGV increases the torque output of a single-bladed VAWT by 206% for tip speed ratio of 0.4. The result also reveals that higher positive torque can be achieved when the blade tangential force at all radial positions is optimized. In conclusion, the ODGV improves the power output of a VAWT and this integrated design promotes the installation of wind energy systems in urban areas.

The technical and economic feasibility study of an innovative wind–solar hybrid renewable energy generation system with rainwater collection feature for electrical energy generation is presented in this paper. The power generated would supply part of the energy requirements of the high-rise building where the system is installed. The system integrates and optimizes several green technologies; including urban wind turbine, solar cell module and rain water collector. The design was conceptualized based on the experiences acquired during the development and testing of a suitable wind turbine for Malaysian applications. It is compact and can be built on top of high-rise buildings in order to provide on-site renewable power to the building. It overcomes the inferior aspect on the low wind speed by channeling and increasing the speed of the high altitude free-stream wind through the power-augmentation-guidevane (PAGV) before it enters the wind turbine at the center portion. The shape or appearance of the PAGV that surrounds the wind turbine can be blended into the building architecture without negative visual impact (becomes part of the building). The design improves the starting behavior of wind turbines. It is also safer to people around and reduces noise pollution. The techno-economic analysis is carried out by applying the life cycle cost (LCC) method. The LCC method takes into consideration the complete range of costs and makes cash flows time-equivalent. The evaluations show that for a system with the PAGV (30 m diameter and 14 m high) and an H-rotor vertical axis wind turbine (17 m diameter and 9 m high) mounted on the top of a 220 m high building, the estimated annual energy savings is 195.2 MW h/year.

In this study, we propose and demonstrate a novel two-Level Partial Least Squares (2L-PLS) architecture for non-invasive blood glucose concentration measurement. A total of 290 Near-Infrared (NIR) spectroscopy readings from six laser diodes with discrete wavelengths of between 1500 nm and 1800 nm are obtained together with blood glucose concentration readings collected via Oral Glucose Tolerance Test (OGTT) experiments from a healthy volunteer over 4 days. While the conventional approach to predicting the blood glucose concentrations is to use a single Partial Least Squares (PLS) or non-linear PLS model, these systems do not achieve a high level of accuracy. As such, a 2L-PLS system consisting of one PLS model at the first level and three at the second level is proposed to enhance the prediction accuracy. A non-linear 2L-PLS system based on the same structure is also investigated in this study. The proposed 2L-PLS systems show improvements of 10 to 12% in the number of predictions that fall below a 5% error margin as compared to single-level PLS systems.

The technical and economic features of a patented V-shape roof guide vane (VRGV) with a solar and wind power generation system mounted on an eco-roof system are presented in this paper. Moreover, this innovative VRGV was investigated on for the purpose of improving the performance of a vertical axis wind turbine (VAWT), which was installed on an eco-roof system to solve the low-efficiency power generation problem of the wind turbines under the condition of a low wind speed. This paper proposes a preliminary study for the performance of the VAWT with the VRGV on a building. This research used a mock-up building with a double slope roof, where a five straight-bladed VAWT was mounted and tested under two conditions, with and without the VRGV. From the comparative experiments, the self-starting performance and rotational speed of the VAWT mounted above a double slope roof with the VRGV have been significantly improved compared to the VAWT without the VRGV. Further, the power coefficient (Cp) of the VAWT can be augmented to about 71.2% increment due to the VRGV design. In addition, numerical simulations by computational fluid dynamics (CFD) were proposed to verify the augmented effect of the Cp of the VAWT under the influence of the VRGV in the experiment. Besides, economic estimation of the VRGV was conducted.

A novel cross axis wind turbine (CAWT) which comprises of a cross axis blades arrangement was presented and investigated experimentally. The CAWT is a new type of wind turbine that extracts wind energy from airflow coming from the horizontal and vertical directions. The wind turbine consists of three vertical blades and six horizontal blades arranged in a cross axis orientation. Hubs in the middle of the CAWT link the horizontal and vertical blades through connectors to form the CAWT. The study used a 45° deflector to guide the oncoming airflow upward (vertical wind direction). The results from the study showed that the CAWT produced significant improvements in power output and rotational speed performance compared to a conventional straight-bladed vertical axis wind turbine (VAWT).

A vertical axis wind turbine (VAWT) was positioned at the discharge outlet of a cooling tower electricity generator. To avoid a negative impact on the performance of the cooling tower and to optimize the turbine performance, the determination of the VAWT position in the discharge wind stream was conducted by experiment. The preferable VAWT position is where the higher wind velocity matches the positive torque area of the turbine rotation. With the proper matching among the VAWT configurations (blade number, airfoil type, operating tip-speed-ratio, etc.) and exhaust air profile, the turbine system was not only able to recover the wasted kinetic energy, it also reduced the fan motor power consumption by 4.5% and increased the cooling tower intake air flow-rate by 11%. The VAWT had a free running rotational speed of 479 rpm, power coefficient of 10.6%, and tip-speed-ratio of 1.88. The double multiple stream tube theory was used to explain the VAWT behavior in the non-uniform wind stream. For the actual size of a cooling tower with a 2.4 m outlet diameter and powered by a 7.5 kW fan motor, it was estimated that a system with two VAWTs (side-by-side) can generate 1 kW of power which is equivalent to 13% of energy recovery.

The integration of a vertical axis wind turbine (VAWT) with the novel omni-directional shroud is proposed. It consists of the upper wall, lower wall and an array of 5 guide-vanes. Wind from all directions is collected radially from a larger area and the geometry of omni-directional shroud creates a venturi effect to increase the wind speed before entering the wind turbine. Guide-vanes aid to channel wind to better angles-of-attack of the turbine blades. Hence, self-starting behavior of the VAWT and the coefficient of power improve. The system was investigated numerically by simulating the wind flow over the omni-directional shroud with a single bladed NACA 0015 airfoil VAWT. In this 2D simulation, the shear stress transport (SST) k-Ȧ turbulence model with the sliding mesh method was used with the tip speed ratio of 5.1 for the wind turbine. The result was verified by re-simulating the experiment published by the Sandia National Laboratories. The result shows that the torque coefficient of the VAWT was increased up to 287% as compared to the bare VAWT. This system improves the performance of the VAWT and it has a great potential to be sited in urban areas for onsite and grid-connected power generation. University of Malaya for the research grant allocated to further develop this design under High Impact Research Grant (D000022-16001). Sincere gratitude is also dedicated to the Malaysian Ministry of Higher Education (MOHE) for Fundamental Research Grant Scheme (FP053-2013B) assigned for this project. Scopus

Pulmonary edema following reexpansion of spontaneous pneumothorax is an uncommon complication. The underlying mechanism of this condition is unclear. We report the hemodynamic characteristics in a series of 7 male patients with spontaneous large (>50%) pneumothoraces of ⩾24 h and correlate the changes with reexpansion pulmonary edema (REPE). A pulmonary artery floatation catheter was inserted and hemodynamic data were obtained before therapeutic chest tube insertion, 1 h after chest tube insertion and the following day. Four (57%) patients developed REPE. There was a tendency for larger pneumothorax to develop REPE. Capillary wedge pressure did not change significantly 1 h after the insertion of chest tube in all our patients. Cardiac output increased significantly in patients who developed REPE compared to those who did not (+1.06 l/min vs −0.27 l/min; P = 0.03) 1 h after insertion of chest tube. One patient did not develop pulmonary edema despite having a large (>80%) pneumothorax. His cardiac output did not rise 1 h after chest tube insertion. REPE is not an uncommon complication following chest tube drainage in patients with large and long-standing pneumothorax. The increase in cardiac output after chest tube insertion may be associated with subsequent development of REPE.

An exhaust air energy recovery turbine generator is designed to recover part of the energy in the discharged air from an exhaust air system. The design is a combination of H-rotor vertical axis wind turbines (installed in cross-wind position), guide-vanes and a diffuser. Its working principle was tested on a scaled model of cooling tower and simulated in a computational fluid dynamic (CFD) package. From the guide-vanes study, optimum guide-vanes arrangement is 100, 70 and 90. The system with optimized guide-vanes arrangement produced the highest torque coefficient compared to the other configurations. The average torque coefficient of the system was increased by 24.3% with the introduction of diffuser and guide-vanes at optimized angles, i.e. from 0.029 to 0.036. From the graph of the torque coefficient versus azimuth angle, the overall positive torque zone was increased with the introduction of the guide-vanes with optimum configuration. The exhaust air energy recovery turbine generator can be another green technology that recovers waste energy from the discharged wind of an exhaust air system for urban areas.

Persistent air-leak in patients with spontaneous pneumothorax (SP) is not uncommon and may present a management dilemma in those who are unfit or unwilling for surgery. Video-assisted thoracoscopic surgery (VATS) has been advocated in the management of patients with broncho-pleural fistulae (air-leak persisting beyond 7 days): however the optimum time for surgical intervention remains unclear. We reviewed the records of 130 episodes of SP in 115 patients over a 2-year period to determine clinical course and outcome, particularly with respect to duration of air-leak. There were 90 first episodes and 40 recurrent episodes. Eighty-one episodes (62%) occurred in patients with underlying lung disease (secondary pneumothorax). Initial management consisted of chest-tube drainage in 104 episodes (80%) occurring in 90 patients, percutaneous needle aspiration in five patients (4%) and observation in 21 episodes (16%) in 20 patients. In the group treated with chest-tube drainage, there was spontaneous resolution of air leak and lung re-expansion in 90 episodes (87%). The overall incidence of broncho-pleural fistula was 34·6%. In the primary SP group, 75% of air-leaks ceased by 7 days and 100% by 15 days. In the secondary SP group, 61% of air-leaks resolved by 7 days and 79% by 14 days, after which time resolution of air-leak proceeded at a much slower rate. Five patients underwent surgery while nine patients were discharged with residual pneumothoraces. There were no major complications or mortality. Based on our findings, we advocate surgery for patients with air-leak persisting beyond 14 days, while favouring a conservative approach before this time, as the majority of air-leaks (especially in patients with primary pneumothorax) would resolve by 14 days.